Axial engagement-controlled variable damper systems and methods

ABSTRACT

The present disclosure provides an axial engagement-controlled variable damper comprising a rotor assembly coupled to a rotor shaft and disposed about an axis of rotation and a stator, coaxially aligned with the rotor assembly. The axial engagement-controlled variable damper may further comprise a flux sleeve, axially movable relative to the rotor assembly between at least a first position and a second position. The flux sleeve may comprise a circumferential flange portion disposed radially between the rotor assembly and the stator, and may be configured to alter magnetic coupling between the stator and the rotor assembly in response being moved axially. The axial-engagement controlled variable damper may be configured to generate a first drag torque in response to the flux sleeve being in the first position and a second drag torque in response to the flux sleeve being in the second position.

FIELD OF THE DISCLOSURE

The present disclosure relates to variable damper systems and methods,and more particularly, to axial engagement-controlled variable dampersystems and methods.

BACKGROUND OF THE DISCLOSURE

Aircraft nose wheel actuators may comprise a rotary damper to addressshimmy in the nose wheel. The rotary damper may comprise a permanentmagnet electric machine configured to create drag on the nose wheelactuator through rotation of a motor shaft and permanent magnet assemblyabout an electromagnetic stator.

Typically, such rotary dampers have a fixed damping coefficient. Stateddifferently, such rotary dampers create drag torque proportional to thespeed of the motor shaft by a fixed damping coefficient. However, dragtorque decreases efficiency of the nose wheel actuator. Rotary damperswith a fixed damping coefficient create constant drag torque, limitingthe responsiveness and performance of the nose wheel actuator. Moreover,size requirements for the nose wheel actuator may increase in order toovercome the fixed drag torque created by rotary dampers having a fixeddamping coefficient.

SUMMARY OF THE DISCLOSURE

In various embodiments, the present disclosure provides an axialengagement-controlled variable damper comprising a rotor assemblycoupled to a rotor shaft and disposed about an axis of rotation, astator, coaxially aligned with the rotor assembly, and a flux sleeve,axially movable relative to the rotor assembly between at least a firstposition and a second position and having a circumferential flangeportion disposed radially between the rotor assembly and the stator. Invarious embodiments, the flux sleeve is configured to alter magneticcoupling between the stator with the rotor assembly in response beingmoved axially. In various embodiments, the axial-engagement controlledvariable damper is configured to generate a first drag torque inresponse to the flux sleeve being in the first position and a seconddrag torque in response to the flux sleeve being in the second position.

In various embodiments, the axial engagement-controlled variable damperfurther comprises an additional flux sleeve axially movable relative tothe rotor assembly and having an additional circumferential flangeportion disposed radially between the rotor assembly and the stator. Invarious embodiments, the axial engagement-controlled variable damperfurther comprises at least one flux sleeve actuator configured to moveat least one of the flux sleeve and the additional flux sleeve. Invarious embodiments, the flux sleeve actuator comprises a passiveactuator. In various embodiments, the flux sleeve actuator comprises ahydraulic actuator. In various embodiments, the axialengagement-controlled variable damper further comprises a rotor hub. Invarious embodiments, the flux sleeve comprises an electromagneticmaterial. In various embodiments, the stator comprises at least one of aplurality of laminations or a conductive winding.

In various embodiments, the present disclosure provides an axialengagement-controlled variable damper comprising a stator disposed aboutan axis of rotation, a rotor assembly, coaxially aligned with thestator, the rotor assembly being axially movable relative to the statorbetween at least a first position and a second position. In variousembodiments, the axial engagement-controlled variable damper isconfigured to generate a first drag torque in response to magneticcoupling between the stator and the rotor assembly when the rotorassembly is in the first position and to generate a second drag torquein response to the rotor assembly being in the second position.

In various embodiments, the rotor assembly comprises a first rotorportion and a second rotor portion. In various embodiments, the axialengagement-controlled variable damper further comprises at least onerotor actuator. In various embodiments, the rotor actuator comprises apassive actuator. In various embodiments, the rotor actuator comprises ahydraulic actuator. In various embodiments, the axialengagement-controlled variable damper further comprises a rotor hub. Invarious embodiments, the stator comprises at least one of a plurality oflaminations or a conductive winding.

In various embodiments, the present disclosure provides a methodcomprising moving at least one of a flux sleeve and at least a portionof a rotor assembly between a first position and a second positionrelative to a stator of an axial engagement-controlled variable damper,and generating a first drag torque in response to the at least one ofthe flux sleeve and at least a portion of the rotor assembly being inthe first position and a second drag torque in response to the at leastone of the flux sleeve and at least a portion of the rotor assemblybeing in the second position.

In various embodiments, in response to the moving increasing axialengagement between the stator and at least a portion of the rotorassembly, the first drag torque is greater than the second drag torque.In various embodiments, in response to the moving decreasing axialengagement between the stator and at least a portion of the rotorassembly, the first drag torque is less than the second drag torque.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present disclosure and are incorporated in, andconstitute a part of, this specification, illustrate variousembodiments, and together with the description, serve to explain theprinciples of the disclosure.

FIG. 1 illustrates a cross section view of a nose wheel actuatorassembly in accordance with various embodiments;

FIG. 2 illustrates a cut-away perspective view of an axialengagement-controlled variable damper in accordance with variousembodiments;

FIG. 3 illustrates another cut-away perspective view of an axialengagement-controlled variable damper in accordance with variousembodiments;

FIG. 4a illustrates another cut-away perspective view of an axialengagement-controlled variable damper in accordance with variousembodiments;

FIG. 4b illustrates test data comparing the performance of an axialengagement-controlled variable damper at various axial positions of aflux sleeve;

FIG. 5a illustrates yet another cut-away perspective view of an axialengagement-controlled variable damper in accordance with variousembodiments;

FIG. 5b illustrates yet another cut-away perspective view of an axialengagement-controlled variable damper in accordance with variousembodiments;

FIG. 5c illustrates test data comparing the performance of an axialengagement-controlled variable damper at various axial positions of arotor assembly;

FIG. 6 illustrates a cross section view of a passive axialengagement-controlled variable damper in accordance with variousembodiments;

FIG. 7a illustrates a close-up cross section view of a portion of apassive axial engagement-controlled variable damper in accordance withvarious embodiments;

FIG. 7b illustrates another close-up cross section view of a portion ofa passive axial engagement-controlled variable damper in accordance withvarious embodiments;

FIG. 8. illustrates a method of using an axial engagement-controlledvariable damper in accordance with various embodiments; and

FIGS. 9-10. illustrate a close-up cross section view of an axialengagement-controlled variable damper with an inside-out configurationin accordance with various embodiments.

DETAILED DESCRIPTION

The detailed description of various embodiments herein makes referenceto the accompanying drawings, which show various embodiments by way ofillustration. While these various embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical, chemical, and mechanical changes may be madewithout departing from the spirit and scope of the disclosure. Thus, thedetailed description herein is presented for purposes of illustrationonly and not of limitation.

For example, the steps recited in any of the method or processdescriptions may be executed in any order and are not necessarilylimited to the order presented. Furthermore, any reference to singularincludes plural embodiments, and any reference to more than onecomponent or step may include a singular embodiment or step. Also, anyreference to attached, fixed, connected, or the like may includepermanent, removable, temporary, partial, full, and/or any otherpossible attachment option. Additionally, any reference to withoutcontact (or similar phrases) may also include reduced contact or minimalcontact.

For example, in the context of the present disclosure, systems andmethods may find particular use in connection with aircraft nose wheelrotary dampers. However, various aspects of the disclosed embodimentsmay be adapted for optimized performance with a variety of dampersystems and methods. As such, numerous applications of the presentdisclosure may be realized.

Referring to FIG. 1 and in accordance with various embodiments, a nosewheel actuator assembly 100 may comprise a motor portion 110, a damperportion 120, and a housing 130 configured to at least partially surroundmotor portion 110 and damper portion 120. The nose wheel actuatorassembly 100 is disposed about an axis of rotation 102. The motorportion 110 is configured to generate power to steer a nose wheel of anaircraft.

In various embodiments, the damper portion 120 may comprise a permanentmagnet electric machine. In such embodiments, the damper portion 120 maycomprise a stator 122 coaxially aligned with a rotor assembly 124 anddisposed about a rotor shaft 126. In various embodiments, the stator 122may comprise a conductive material. In various embodiments, the rotorassembly 124 may comprise one or more permanent magnets 125. Duringrotation of the rotor shaft 126, the permanent magnets 125 disposed onthe rotor assembly 124 rotate relative to the stator 122, creating eddycurrents in the damper portion 120. Such eddy currents createelectromagnetic drag torque on the motor portion 110. FIG. 1 provides ageneral understanding of various the portions of a nose wheel actuatorassembly, and is not intended to limit the disclosure.

In various embodiments, an axial engagement-controlled variable dampermay comprise a stator coaxially aligned with, and disposed about, arotor assembly, such that the stator is configured to generate a firstdrag torque in response to magnetic coupling of the stator with therotor assembly. In various embodiments, the axial engagement-controlledvariable damper may be configured to adjustably control magneticcoupling of the stator with the rotor assembly through axial translationof a portion of the axial engagement-controlled variable damper. Invarious embodiments, axial translation of a flux sleeve at leastpartially between the stator and the rotor assembly may decreasemagnetic coupling of the stator with the rotor assembly. In variousembodiments, axial translation of the rotor assembly at least partiallyinto axial alignment with the stator may increase magnetic coupling ofthe stator with the rotor assembly. In various embodiments, axialtranslation of the rotor assembly at least partially out of axialalignment with the stator may decrease magnetic coupling of the statorwith the rotor assembly.

With reference to FIGS. 2a, 3a, and 4a , an axial engagement-controlledvariable damper 200 may comprise a rotor assembly 240. In variousembodiments, the rotor assembly 240 may be coupled to a rotor shaft 230and disposed about an axis of rotation 102. In various embodiments, therotor assembly 240 and the rotor shaft 230 are configured to rotateabout the axis of rotation 102. In various embodiments, the rotorassembly 240 may comprise a plurality of permanent magnets arranged in agenerally cylindrical pattern facing radially outward from the rotorshaft 230. In various embodiments, the rotor assembly 240 may furthercomprise a retention sleeve portion 241 configured to couple theplurality of permanent magnets to the rotor assembly 240. In variousembodiments, the axial engagement-controlled variable damper 200 mayfurther comprise a rotor hub 243. In various embodiments, the rotor hub243 may be configured to receive the rotor assembly 240 and/or couplethe rotor assembly 240 to the rotor shaft 230.

In various embodiments, a stator 220 may be coaxially aligned with, anddisposed about, the rotor assembly 240. In various embodiments, thestator 220 may comprise an electromagnetic material. In variousembodiments, the stator 220 may comprise at least one of a metal, ametal alloy, or a combination of one or more metals or alloys. Invarious embodiments, the stator 220 may comprise steel. However, invarious embodiments, the stator 220 may comprise any material suitablefor use in the axial engagement-controlled variable damper 200.

In various embodiments, the stator 220 may comprise a plurality oflaminations. In various embodiments, the stator 220 may lack laminationsand/or may comprise a unitary member. In various embodiments, the stator220 may further comprise one or more stator windings 222. The statorwindings 222 may comprise a conductive wire and/or foil wound at leastpartially about the stator 220. In various embodiments, the statorwindings 222 may act as a rotational sensor.

In various embodiments, rotation of the rotor shaft 230 causes rotationof the rotor assembly 240 and the plurality of permanent magnets withinthe stator 220. In various embodiments, such rotation may cause magneticcoupling of the rotor assembly 240 with the stator 220. In variousembodiments, such rotation may create eddy currents in the stator 220.Stated differently, in various embodiments, the interaction of theplurality of permanent magnets and the stator 220 may create alternatingmagnetic flux within the axial engagement-controlled variable damper200. In various embodiments, such magnetic coupling and/or alternatingmagnetic flux may generate a first drag torque.

In various embodiments, the axial engagement-controlled variable damper200 may further comprise a flux sleeve 250 coaxially aligned with therotor shaft 230 about the axis of rotation 102. In various embodiments,the flux sleeve 250 may comprise a radial portion 253 and acircumferential flange portion 254, wherein the circumferential flangeportion 254 extends in an axial direction from an outer circumference ofthe radial portion 253. In various embodiments, the circumferentialflange portion 254 of flux sleeve 250 may be disposed radially outwardof the rotor assembly 240 and radially inward of the stator 220.

In various embodiments, the flux sleeve 250 may comprise anelectromagnetic material. In various embodiments, the flux sleeve 250may comprise steel, aluminum, and/or any other suitable metal, alloy, ora composite material configured to communicate magnetic flux. In variousembodiments, the flux sleeve 250 may be operatively coupled to the rotorassembly 240 and configured to rotate with the rotor assembly 240 suchthat interaction of the rotor assembly 240 with the flux sleeve 250 doesnot cause the axial engagement-controlled variable damper 200 togenerate drag torque.

In various embodiments, the flux sleeve 250 is configured for axialtranslation and/or insertion between the rotor assembly 240 and thestator 220. In various embodiments, such insertion may alter magneticcoupling of the stator 220 with the rotor assembly 240. Stateddifferently, magnetic coupling of the stator 220 with the rotor assembly240 may be disrupted and/or decreased at portions of the axialengagement-controlled variable damper 200 at which the stator 220 andthe rotor assembly 240 are not in direct axial engagement but, instead,at which the flux sleeve 250 is disposed axially between the stator 220and the rotor assembly 240.

In various embodiments, the axial engagement-controlled variable damper200 may further comprise an additional flux sleeve 251. In variousembodiments, the flux sleeve 250 may be disposed at a first axial end246 of the rotor assembly 240 and the additional flux sleeve 251 may bedisposed at a second axial end 247 of the rotor assembly 240. In variousembodiments, the first sleeve 250 and the additional flux sleeve 251 maybe disposed on opposite sides of an axial plane 104 which transverselybisects the stator 220 and the rotor assembly 240 substantially at theiraxial midpoints. In various embodiments, the circumferential flangeportion 254 of the flux sleeve 250 may extend from the first axial end246 toward the axial plane 104. In various embodiments, thecircumferential flange portion 254 of the additional flux sleeve 251 mayextend from the second axial end 247 toward the axial plane 104.

In various embodiments, the flux sleeve 250 and the additional fluxsleeve 251 may be configured for axial translation towards or away fromthe axial plane 104. In various embodiments, an axial position of theflux sleeve 250 and/or the additional flux sleeve 251 may affect dampingperformance of the axial engagement-controlled variable damper 200. Forexample, FIG. 2a illustrates a first axial position of the flux sleeve250 and the additional flux sleeve 251 in accordance with variousembodiments. In various embodiments, the first axial position maycomprise insertion of the circumferential flange portion 254 of the fluxsleeve 250 and/or the additional flux sleeve 251 between the stator 220and the rotor assembly 240 such that the radial portion 253 is disposedsubstantially adjacent to the first axial end 246 and/or the secondaxial end 247. In various embodiments, the first axial position maycause a first alteration of magnetic coupling between the stator 220 andthe rotor assembly 240; stated differently, the first axial position maydecrease, eliminate, and/or minimize magnetic engagement of the stator220 with the rotor assembly 240.

For example, FIG. 3a illustrates a second axial position of the fluxsleeve 250 and the additional flux sleeve 251 in accordance with variousembodiments. In various embodiments, the second axial position maycomprise partial insertion of the circumferential flange portion 254 ofthe flux sleeve 250 and/or the additional flux sleeve 251 between thestator 220 and the rotor assembly 240. In various embodiments, thesecond axial position may cause a second alteration of magnetic couplingbetween the stator 220 and the rotor assembly 240; stated differently,the second axial position may partially disrupt magnetic coupling and/ormay partially limit magnetic engagement of the stator 220 with the rotorassembly 240.

For example, FIG. 4a illustrates a third axial position of the fluxsleeve 250 and the additional flux sleeve 251 in accordance with variousembodiments. In various embodiments, the third axial position maycomprise minimal or no insertion of the circumferential flange portion254 of the flux sleeve 250 and/or the additional flux sleeve 251 betweenthe stator 220 and the rotor assembly 240. In various embodiments, thethird axial position may cause a third alteration of magnetic couplingbetween the stator 220 and the rotor assembly 240; stated differently,the third axial position may increase magnetic coupling and/or magneticengagement of the stator 220 with the rotor assembly 240.

As illustrated in FIG. 4b , the axial position of the flux sleeve 250and/or the additional flux sleeve 251 may affect torque generated by theaxial engagement-controlled variable damper 200. FIG. 4b shows acomparison between damping performance at various levels of axialengagement and/or insertion of the flux sleeve 250 and/or the additionalflux sleeve 251 between the stator 220 and the rotor assembly 240. Thedamper rotational speed is shown on the x axis and the drag torqueproduced is shown on the y axis. As shown in FIG. 4b , increasedinsertion of the flux sleeve 250 and/or the additional flux sleeve 251between the stator 220 and rotor assembly 240 decreases the dampertorque produced at various damper rotational speeds.

In various embodiments and with reference again to FIG. 2a , the axialengagement-controlled variable damper 200 may further comprise a fluxsleeve actuator configured to translate at least one of the flux sleeve250 or the additional flux sleeve 251 along the axis of rotation 102 inat least one of a first direction or a second direction. In variousembodiments, the flux sleeve actuator may comprise an active actuator.In various embodiments, the flux sleeve actuator may comprise a passiveactuator. In various embodiments, the flux sleeve actuator may comprisea hydraulic actuator, a pneumatic actuator, and/or a mechanicalactuator.

In various embodiments, the axial engagement-controlled variable damper200 may further comprise at least one return spring 270. In variousembodiments, the return spring 270 may be operatively coupled to atleast one of the flux sleeve 250 or the additional flux sleeve 251. Invarious embodiments, the return spring 270 may be configured to apply anopposing axial force to at least one of the flux sleeve 250 or theadditional flux sleeve 251 in at least one of a first direction or asecond direction.

In various embodiments, the flux sleeve actuator may comprise ahydraulic actuator in fluid communication with at least one of the fluxsleeve 250 or the additional flux sleeve 251. In such embodiments, thehydraulic actuator may comprise a port 260 configured to receivehydraulic fluid and in fluid communication with an oil channel 261. Invarious embodiments, the oil channel 261 may be at least partiallydisposed in rotor shaft 230, and/or the rotor hub 243. In variousembodiments, increased oil pressure through the oil channel 261 maydisplace at least one of the flux sleeve 250 and the additional fluxsleeve 251 in an axial direction along the axis of rotation 102.

In various embodiments, the hydraulic actuator may be an activeactuator. In various embodiments, the hydraulic actuator may becontrolled by a controller configured to adjustably communicatehydraulic fluid through oil channel 261. In various embodiments, thecontroller may comprise a processor configured to implement variouslogical operations in response to execution of instructions, forexample, instructions stored on a non-transitory, tangible,computer-readable medium.

In various embodiments, the rotor hub 243 may operatively couple to atleast one of the flux sleeve 250 or the additional flux sleeve 251 andmay be configured to bring the hydraulic actuator into fluidcommunication therewith. In such embodiments, the rotor hub 243 maycouple to at least one of the flux sleeve 250 and the additional fluxsleeve 251 by way of at least one rotor hub aperture 244 that engages atleast one mating flux sleeve piston 252. In various embodiments, themating flux sleeve piston 252 may comprise a generally cylindricalpiston that engages a generally cylindrical rotor hub aperture 244. Invarious embodiments, the rotor hub 243 couples to the flux sleeve 250 byway of a plurality of rotor hub apertures and flux sleeve pistons. Invarious embodiments, the mating flux sleeve piston 252 may comprise agenerally annular projection that engages a generally annular rotor hubaperture 244.

In various embodiments, the hydraulic actuator and the oil channel 261may be in fluid communication with the rotor hub aperture 244 and theflux sleeve piston 252 such that communication of oil into the rotor hubaperture 244 translates the flux sleeve piston 252 and at least one ofthe flux sleeve 250 or the additional flux sleeve 251 in an axialdirection toward the axial plane 104. In various embodiments, such axialtranslation causes compression of the return spring 270. Accordingly, invarious embodiments, an axial position of the flux sleeve 250 and theadditional flux sleeve 251 may be adjustably controlled by the hydraulicactuator.

In various embodiments, the hydraulic actuator may be a passiveactuator. In various embodiments, the hydraulic actuator may adjustablycommunicate hydraulic fluid through oil channel 261 in response torotation of the rotor shaft 230. In various embodiments, the flux sleeveactuator may comprise a flyweight actuator (described below).

Although the various embodiments shown have illustrated an axialengagement-controlled variable damper having a convention configuration,wherein the permanent magnets are disputed co-axially within the stator,in various embodiments, the axial engagement-controlled variable dampermay comprise an inside-out configuration, wherein the permanent magnetsare co-axially disputed around an outside circumference of the stator.In various embodiments, the flux sleeve may perform the same functionand may translate axially, moving between the rotor assembly and thestator.

With reference now to FIGS. 5a and 5b , an axial engagement-controlledvariable damper 500 may comprise a rotor assembly 540, a rotor shaft530, and a stator 520 as already described herein. In variousembodiments, the axial engagement-controlled variable damper 500 mayfurther comprise a rotor hub 543 (discussed below). In variousembodiments, the axial engagement-controlled variable damper 500 mayfurther comprise a rotor actuator configured to translate the rotorassembly 540 axially along the axis of rotation 102 and relative to thestationary stator 520. In various embodiments, such axial translationmay alter magnetic coupling between the stator 220 and the rotorassembly 240. Stated differently, magnetic coupling of the stator 220with the rotor assembly 240 may be disrupted at the portions of theaxial engagement-controlled variable damper 200 at which the stator 220and the rotor assembly 240 are not in direct axial engagement as aresult of axial translation of the rotor assembly 240.

In various embodiments, the axial engagement-controlled variable damper500 may comprise a split rotor assembly having a first rotor portion 548and a second rotor portion 549. In various embodiments, the axialengagement-controlled variable damper 500 may comprise an axial plane104 which transversely bisects the stator 520 substantially at its axialmidpoint. In various embodiments, the first rotor portion 548 and thesecond rotor portion 549 may be disposed substantially axially adjacentto one another on opposite sides of the axial plane 104.

In various embodiments, at least one of the rotor assembly 540, thefirst rotor portion 548, and the second rotor portion 549 may beconfigured for axial translation towards or away from the axial plane104. In various embodiments, an axial position of the rotor assembly540, the first rotor portion 548, and/or the second rotor portion 549may affect damping performance of the axial engagement-controlledvariable damper 500. For example, FIG. 5a illustrates a first axialposition of the first rotor portion 548 and the second rotor portion 549in accordance with various embodiments. In various embodiments, thefirst axial position may comprise the axial engagement between stator520 and the rotor assembly 540 such that substantially all of the rotorassembly 540 is axially aligned with the stator 520. In variousembodiments, the first axial position may cause or increase magneticcoupling between the stator 520 and the rotor assembly 540.

For example, FIG. 5b illustrates a second axial position of the firstrotor portion 548 and the second rotor portion 549 in accordance withvarious embodiments. In various embodiments, the second axial positionmay comprise partial displacement of the first rotor portion 548 and thesecond rotor portion 549 away from the axial plane 104 and out of axialengagement with the stator 520. In various embodiments, the second axialposition may cause partial disruption of magnetic coupling of the stator520 with the rotor assembly 540; stated differently, the second axialposition may partially limit axial engagement of the stator 220 with therotor assembly 240, thereby decreasing drag torque generated by theaxial engagement-controlled variable damper 500.

As illustrated in FIG. 5c , the axial position of the rotor assembly540, the first rotor portion 548, and the second rotor portion 549 mayaffect torque generated by the axial engagement-controlled variabledamper 500. FIG. 5c shows a comparison between damping performance atvarious levels of axial engagement between the stator 520 and at leastone of the rotor assembly 540, the first rotor portion 548, and thesecond rotor portion 549. The damper rotational speed is shown on the xaxis and the drag torque produced is shown on the y axis. As shown inFIG. 5c , increased axial engagement between the stator 220 and at leastone of the rotor assembly 540, the first rotor portion 548, and thesecond rotor portion 549 increases the damper torque produced at variousdamper rotational speeds.

With reference again to FIG. 5a and FIG. 5b , In various embodiments,the axial engagement-controlled variable damper 500 may further comprisea rotor actuator configured to translate at least one of the rotorassembly 540, the first rotor portion 548, or the second rotor portion549 along the axis of rotation 102 in at least one of a first directionor a second direction. In various embodiments, the rotor actuator maycomprise an active actuator. In various embodiments, the rotor actuatormay comprise a passive actuator. In various embodiments, the rotoractuator may comprise a hydraulic actuator, a pneumatic actuator, and/ora mechanical or electromechanical actuator.

In various embodiments, the rotor actuator may comprise a hydraulicactuator in fluid communication with at least one of the rotor assembly540, the first rotor portion 548, or the second rotor portion 549. Insuch embodiments, the hydraulic actuator may comprise a port 560configured to receive hydraulic fluid and in fluid communication with anoil channel 561. In various embodiments, the oil channel 561 may be atleast partially disposed in the rotor shaft 530, and/or the rotor hub543. In various embodiments, increased oil pressure through the oilchannel 561 may displace at least one of the rotor assembly 540, thefirst rotor portion 548, or the second rotor portion 549 in an axialdirection along the axis of rotation 102.

In various embodiments, the hydraulic actuator may be an activeactuator. In various embodiments, the hydraulic actuator may becontrolled by a controller configured to adjustably communicatehydraulic fluid through oil channel 561. In various embodiments, thecontroller may comprise a processor configured to implement variouslogical operations in response to execution of instructions, forexample, instructions stored on a non-transitory, tangible,computer-readable medium.

In various embodiments, the rotor hub 543 may operatively couple to atleast one of the rotor assembly 540, the first rotor portion 548, or thesecond rotor portion 549 and may be configured to bring the hydraulicactuator into fluid communication therewith. In such embodiments, therotor hub 543 may couple to at least one of the rotor assembly 540, thefirst rotor portion 548, or the second rotor portion 549 by way of atleast one rotor hub projection 544 that engages at least one matingrotor assembly aperture 552. In various embodiments, the rotor hubprojection 544 may comprise a generally cylindrical projection thatengages a generally cylindrical mating rotor assembly aperture 552. Invarious embodiments, the rotor hub 543 couples to the rotor assembly 540by way of a plurality of rotor assembly apertures and rotor hubprojections. In various embodiments, the rotor assembly aperture maycomprise a generally annular aperture that engages a generally annularmating rotor hub projection.

In various embodiments, the hydraulic actuator and the oil channel 561may be in fluid communication with the rotor hub projection 544 and therotor assembly aperture 552 such that communication of oil into therotor hub projection 544 translates at least one of the rotor assembly540, the first rotor portion 548, or the second rotor portion 549 in anaxial direction away from the axial plane 104 and out of axialengagement with the stator 520. Accordingly, in various embodiments, anaxial position of at least one of the rotor assembly 540, the firstrotor portion 548, or the second rotor portion 549 may be adjustablycontrolled by the hydraulic actuator.

In various embodiments, the hydraulic actuator may be a passiveactuator. In various embodiments, the hydraulic actuator may adjustablycommunicate hydraulic fluid through oil channel 561 in response torotation of the rotor shaft 530. In various embodiments and withreference to FIGS. 6, 7 a, and 7 b, the rotor actuator may comprise aflyweight actuator 610. In various embodiments, the flyweight actuator610 may comprise a flyweight mass 612 disposed radially inward of therotor assembly 640 and operatively coupled to a portion of the axialengagement-controlled variable damper 600 configured for axialtranslation along the axis of rotation 102. In various embodiments, theflyweight actuator 610 may be configured to rotate with the rotor shaft630 about the axis of rotation 102. In various embodiments, theflyweight actuator 610 may be operatively coupled to at least one of therotor assembly 640, the first rotor portion 548, or the second rotorportion 549 (with momentary reference to FIGS. 5a and 5b ).

In various embodiments the flyweight spring 614 may act on the flyweightmass 612 in a radially inward direction. In various embodiments, duringrotation of the rotor shaft 630 and the flyweight actuator 610, theflyweight mass 612 may translate radially outward from the axis ofrotation 102, causing compression of the flyweight spring 614 and axialtranslation of at least one of the rotor assembly 640, the first rotorportion 548, or the second rotor portion 549 (with momentary referenceto FIGS. 5a and 5b ). In various embodiments, the flyweight hinges 616may be configured such that translation of the flyweight mass 612 causesdisplacement of at least one of the rotor assembly 640, the first rotorportion 548, or the second rotor portion 549 (with momentary referenceto FIGS. 5a and 5b ). In various embodiments, the flyweight hinges 616may be adjusted and/or configured to achieve a desired axial position ofat least one of the rotor assembly 640, the first rotor portion 548, orthe second rotor portion 549 (with momentary reference to FIGS. 5a and5b ) and, accordingly, a desired damping performance of the axialengagement-controlled variable damper 600.

Various embodiments described hereinbefore comprise a rotor assemblyhaving a conventional configuration, wherein permanent magnets arearranged in a generally cylindrical pattern facing radially outward fromthe axis of rotation toward the stator. One skilled in the art willappreciate that in various embodiments, any of the hereinbeforedescribed embodiments may comprise an axial engagement-controlledvariable damper having an “inside out” configuration. Stateddifferently, in various embodiments, an axial engagement-controlledvariable damper may comprise a stator disposed radially inward of arotor assembly, the rotor assembly comprising permanent magnets arrangedin a generally cylindrical pattern facing radially inward towards thestator. With reference to FIG. 9, an axial engagement-controlledvariable damper 300 may comprise a stator 320 disposed radially inwardof a rotor assembly 340 and a flux sleeve 350. With reference to FIG.10, an axial engagement-controlled variable damper 400 may comprise astator 420 disposed radially inward of a rotor assembly 440. In variousembodiments, rotor assembly 440 may comprise a first rotor portion 448and a second rotor portion 449.

With reference to FIG. 8, in various embodiments, a method 800 may allowvariable control of drag torque generated by an axialengagement-controlled variable damper. In various embodiments, thedegree of axial engagement between a stator and a rotor assembly may bedirectly proportional to the drag torque generated by the axialengagement-controlled variable damper. In various embodiments, thedegree of axial engagement between a stator and a rotor assembly may becontrolled, adjusted, and/or varied by moving a flux sleeve or a portionof the rotor assembly relative to the stator. In various embodiments,drag torque generated by an axial engagement-controlled variable damperis continuously variable.

In various embodiments, the method 800 may comprise moving a portion ofthe axial engagement-controlled variable damper between at least a firstposition and a second position (Step 801). In various embodiments, themethod 800 may comprise moving the flux sleeve 250 between at least afirst position and a second position. In various embodiments, the movingcauses an increase in axial engagement between the stator 220 and therotor assembly 240 through axial translation of the flux sleeve 250 awayfrom the axial plane 104. In various embodiments, the moving causes adecrease in axial engagement between the stator 220 and the rotorassembly 240 through axial translation of the flux sleeve 250 toward theaxial plane 104.

In various embodiments, the method 800 may comprise moving at least oneof the rotor assembly 540, the first rotor portion 548, or the secondrotor portion 549 between at least a first position and a secondposition. In various embodiments, the moving causes an increase in axialengagement between the stator 520 and the rotor assembly 540 throughaxial translation of at least a portion of the rotor assembly 540 towardthe axial plane 104. In various embodiments, the moving causes adecrease in axial engagement between the stator 520 and the rotorassembly 540 through axial translation of at least a portion of therotor assembly 540 away from the axial plane 104.

In various embodiments, the method 800 further comprises generating afirst drag torque in response to at least one of the flux sleeve and atleast a portion of the rotor assembly being in the first position (Step802). In various embodiments, the method 800 may further comprisegenerating a second drag torque in response to at least one of the fluxsleeve and at least a portion of the rotor assembly being in the secondposition (Step 803).

In various embodiments, the generating may be by an axialengagement-controlled variable damper 200 comprising a flux sleeve 250.In various embodiments, the generating may be by an axialengagement-controlled variable damper 500 comprising a rotor assembly540 configured for axial translation.

In various embodiments, in response to the moving increasing axialengagement between the stator and at least a portion of the rotorassembly, the first drag torque is greater than the second drag torque.In various embodiments, in response to the moving decreasing axialengagement between the stator and at least a portion of the rotorassembly, the first drag torque is greater than the second drag torque.Stated differently, in various embodiments, an amount of drag torquegenerated by the axial engagement-controlled variable damper may beinversely proportional to an amount of axial engagement between thestator and at least a portion of the rotor assembly. In variousembodiments, an axial position of at least one of the flux sleeve and atleast a portion of the rotor assembly may be continuously variable. Invarious embodiments the amount of axial engagement between the statorand at least a portion of the rotor assembly may be continuouslyvariable. In various embodiments, a continuously variable amount ofaxial engagement between the stator and at least a portion of the rotorassembly may generate a continuously variable drag torque.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosure. The scope of the disclosure is accordinglyto be limited by nothing other than the appended claims, in whichreference to an element in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.”Moreover, where a phrase similar to “at least one of A, B, or C” is usedin the claims, it is intended that the phrase be interpreted to meanthat A alone may be present in an embodiment, B alone may be present inan embodiment, C alone may be present in an embodiment, or that anycombination of the elements A, B and C may be present in a singleembodiment; for example, A and B, A and C, B and C, or A and B and C.Different cross-hatching is used throughout the figures to denotedifferent parts but not necessarily to denote the same or differentmaterials.

Devices and methods are provided herein. In the detailed descriptionherein, references to “one embodiment”, “an embodiment”, “variousembodiments”, etc., indicate that the embodiment described may include aparticular feature, structure, or characteristic, but every embodimentmay not necessarily include the particular feature, structure, orcharacteristic. Moreover, such phrases are not necessarily referring tothe same embodiment. Further, when a particular feature, structure, orcharacteristic is described in connection with an embodiment, it issubmitted that it is within the knowledge of one skilled in the art toaffect such feature, structure, or characteristic in connection withother embodiments whether or not explicitly described. After reading thedescription, it will be apparent to one skilled in the relevant art(s)how to implement the disclosure in alternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element herein is to be construed under theprovisions of 35 U.S.C. 112(f) unless the element is expressly recitedusing the phrase “means for.” As used herein, the terms “comprises”,“comprising”, or any other variation thereof, are intended to cover anon-exclusive inclusion, such that a process, method, article, orapparatus that comprises a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus.

What is claimed is:
 1. An axial engagement-controlled variable dampercomprising: a rotor assembly coupled to a rotor shaft and disposed aboutan axis of rotation; a stator, coaxially aligned with, and disposedradially about, the rotor assembly; and a flux sleeve, axially movablerelative to the rotor assembly between at least a first position and asecond position and having a circumferential flange portion disposedradially outward of the rotor assembly and radially inward of thestator, the flux sleeve being configured to alter magnetic couplingbetween the stator and the rotor assembly in response to being movedaxially, the axial-engagement controlled variable damper beingconfigured to generate a first drag torque in response to the fluxsleeve being in the first position and a second drag torque in responseto the flux sleeve being in the second position.
 2. The axialengagement-controlled variable damper of claim 1, wherein at least oneof the first drag torque and the second drag torque is continuouslyvariable.
 3. The axial engagement-controlled variable damper of claim 1,further comprising: an additional flux sleeve being axially movablerelative to the rotor assembly and having an additional circumferentialflange portion disposed radially outward of the rotor assembly andradially inward of the stator.
 4. The axial engagement-controlledvariable damper of claim 3, further comprising at least one flux sleeveactuator configured to move at least one of the flux sleeve and theadditional flux sleeve.
 5. The axial engagement-controlled variabledamper of claim 4, wherein the at least one flux sleeve actuatorcomprises a passive actuator.
 6. The axial engagement-controlledvariable damper of claim 4, wherein the at least one flux sleeveactuator comprises a hydraulic actuator.
 7. The axialengagement-controlled variable damper of claim 6, further comprising arotor hub.
 8. The axial engagement-controlled variable damper of claim2, wherein the stator comprises at least one of a plurality oflaminations or a conductive winding.
 9. An axial engagement-controlledvariable damper comprising: a stator disposed about an axis of rotation;a rotor assembly, coaxially aligned with, and disposed inward of, thestator, the rotor assembly being axially movable relative to the statorbetween at least a first position and a second position, the axialengagement-controlled variable damper being configured to generate afirst drag torque in response to magnetic coupling between the statorand the rotor assembly when the rotor assembly is in the first positionand to generate a second drag torque in response to the rotor assemblybeing in the second position.
 10. The axial engagement-controlledvariable damper of claim 9, wherein the rotor assembly comprises a firstrotor portion and a second rotor portion.
 11. The axialengagement-controlled variable damper of claim 10, further comprising atleast one rotor actuator.
 12. The axial engagement-controlled variabledamper of claim 11, wherein the rotor actuator comprises a passiveactuator.
 13. The axial engagement-controlled variable damper of claim11, wherein the rotor actuator comprises a hydraulic actuator.
 14. Theaxial engagement-controlled variable damper of claim 13, furthercomprising a rotor hub.
 15. The axial engagement-controlled variabledamper of claim 11, wherein the stator comprises at least one of aplurality of laminations or a conductive winding.
 16. A methodcomprising: moving at least one of a flux sleeve and at least a portionof a rotor assembly between a first position and a second positionrelative to a stator of an axial engagement-controlled variable damper;and generating a first drag torque in response to the at least one ofthe flux sleeve and at least a portion of the rotor assembly being inthe first position and a second drag torque in response to the at leastone of the flux sleeve and at least a portion of the rotor assemblybeing in the second position; wherein the axial engagement-controlledvariable damper being configured to generate the first drag torque andthe second drag torque.
 17. The method of claim 16, wherein, in responseto the moving increasing axial engagement between the stator and atleast a portion of the rotor assembly, the first drag torque is greaterthan the second drag torque.
 18. The method of claim 16, wherein, inresponse to the moving decreasing axial engagement between the statorand at least a portion of the rotor assembly, the first drag torque isless than the second drag torque.
 19. The method of claim 16, whereinthe axial engagement-controlled variable damper comprises: the rotorassembly coupled to a rotor shaft and disposed about an axis ofrotation; a stator, coaxially aligned with, and disposed about, therotor assembly; and the flux sleeve, axially movable relative to therotor assembly between at least the first position and the secondposition and having a circumferential flange portion disposed radiallyoutward of the rotor assembly and radially inward of the stator, theflux sleeve being configured to alter magnetic coupling between thestator with the rotor assembly in response being moved axially, theaxial-engagement controlled variable damper being configured to generatethe first drag torque in response to the flux sleeve being in the firstposition and the second drag torque in response to the flux sleeve beingin the second position.
 20. The method of claim 16, wherein the axialengagement-controlled variable damper comprises: a stator disposed aboutan axis of rotation; and the rotor assembly, coaxially aligned with, anddisposed inward of, the stator, the rotor assembly being axially movablerelative to the stator between at least the first position and thesecond position, the axial engagement-controlled variable damper beingconfigured to generate the first drag torque in response to magneticcoupling between the stator and the rotor assembly when the rotorassembly is in the first position and to generate the second drag torquein response to the rotor assembly being in the second position.